Part 7 – Acids, Alkalis and Salt Preparation
1. For this questions, make use of page 5 of your data booklet.
From the answer grid below, select the 2 letters which contain substances which could be used to make:
(a) an acid (b) an alkali (c) a neutral solution
2. Describe how acid rain is formed and describe some of the effects of acid rain.
3
(a) Explain how nitrogen and oxygen can combine in a car engine.
(b) Name a metal which can be used as a catalyst in the catalytic convertor.
(c) Name the two pollutant gases changed by the catalyst and describe what they are changed into.
4. Explain why solid citric acid does not conduct electricity yet when it dissolves in water it does conduct.
5. Electrolysis of acids can be used to confirm the presence of hydrogen ions.
(a) At which electrode will hydrogen form?
(b) Write an ion-electron equation to show the formation of hydrogen (use page 7 of the data booklet)
(c) State the test for hydrogen gas
6. Explain why pure water conducts electricity.
7. The grid below contains various statements which apply to solutions
(a) Which 3 boxes apply to an acid?
(b) Which 2 boxes apply to pure water?
(c) Which 3 boxes apply to an alkali?
8. Write ionic formula for the following:
(a) sodium hydroxide
(b) hydrochloric acid
(c) nitric acid
(d) sulphuric acid
(e) potassium hydroxide
9. An electric current was passed through different solutions. The results are shown in the table.
(a) From the results, suggest a general statement which can be made about acids.
(b) From the results, predict the products at the positive and negative electrodes if potassium nitrate solution is used.
(c) Explain why potassium chloride conducts electricity when dissolved in water, but not when solid.
10. Give two examples of everyday neutralisation.
11. Which of the following is not an example of a salt
12. Name the salt formed in the following reactions:
(a) Hydrochloric acid + potassium hydroxide (b) Sulphuric acid + calcium hydroxide
(c) Lithium hydroxide + nitric acid (d) Sodium hydroxide + sulphuric acid
13. Write chemical equations for the reactions in question 5.
14. When substance X was added to hydrochloric acid a colourless gas Y (which turned limewater chalky) was given off. A flame test on X gave a bright yellow colour.
(a) Name gas Y
(b) What does the flame test tell you about X?
(c) Name X and write its chemical formula.
15. Write: (a) word equations (b) chemical equations for the following reactions:
(i) sodium hydroxide + sulphuric acid (ii) calcium carbonate + hydrochloric acid
(iii) copper(II) carbonate + nitric acid (iii) potassium carbonate + sulphuric acid
16. Write (a) word equations (b) chemical equations for the following reactions:
(i) magnesium + hydrochloric acid (ii) calcium oxide + sulphuric acid
(iii) copper (II) oxide + nitric acid (iv) sodium hydroxide + sulphuric acid
(v) sodium oxide + nitric acid (vi) zinc + hydrochloric acid
17. A pupil tried to make copper (II) sulphate by reacting copper with sulphuric acid. Explain why this method would not work, and suggest an alternative method for making copper (II) sulphate.
18. Re-write the following equations, omitting spectator ions, to show the ions which react
19. Name the insoluble salt formed in the following precipitation reactions:
20.
(a) Re-write the word equations in Q.12 as completed chemical equations, showing ions.
(b) Circle the spectator ions in each of your chemical equations.
21.
20cm3of 1mol/l sodium hydroxide was neutralised by 40cm3 hydrochloric acid. Calculate the concentration of the acid.
22.
50cm3 of potassium hydroxide was required to neutralise 25cm3 of sulphuric acid (concentration 2 mol/l). Calculate the concentration of the potassium hydroxide.
23.
100cm3 calcium hydroxide, concentration 2 mol/l was required to neutralise hydrochloric acid, concentration 3 mol/l. Calculate the volume of hydrochloric acid.
24. A pupil carried out a titration using the chemicals and apparatus shown below.
(a) How would the pupil know when to stop adding acid from the burette?
(b)
(i) What average volume should be used to calculate the number of moles of sulphuric acid needed to neutralise the potassium hydroxide solution?
(ii) Calculate the number of moles of sulphuric acid in this average volume. Show your working clearly.
(iii) The equation for the titration reaction is
Calculate the number of moles of potassium hydroxide in 20cm3 of the potassium hydroxide solution. Show your working clearly.
25. Bones are formed when calcium ions and phosphate ions combine to form insoluble calcium phosphate, Ca3(PO4)2 This reaction can be reproduced in the laboratory by adding a solution of calcium chloride to a solution of sodium phosphate.
(a) Identify the spectator ions in the above equation.
(b) What technique could be used to remove the calcium phosphate from the mixture?
26. Roy was instructed to make 50cm3 of a 1mol/l solution of copper chloride, CuCl2. Calculate the mass in grams of copper chloride needed.
27. Use the information in the table to answer the questions which follow
(a) Identify the 2 bases.
(b) Identify the compound which could be prepared by precipitation. You may wish to refer to page 5 of the data booklet.
28. Precipitation reactions can be used to prepare some salts.
(a) Identify the salt which can be prepared by a precipitation reaction.
(b) Identify the 2 soluble salts which would form a precipitate when mixed.
You may wish to use page 5 of the data booklet
29. 
(a) Identify the 2 statements which can be applied to both dilute hydrochloric acid and dilute sulphuric acid.
(b) Identify the statement which can be applied to sodium chloride solution but not to dilute hydrochloric acid.
30. 
